check out this homepage, it is split toned in hypo-alum.

ilford galerie turns a nice coppery brown, ilford warmtone turn a nice reddish brown, in hypo alum. not as brown as what i see from your scans but very nice. if you go this way let me know, i have some experience with it - it can be finicky.

i think tim rudman's book is a good suggestion and i think you are on the right track using warmtone as a base, probably with a brown or thiocarbamide toner.